This invention relates to a method of controlling the heating effected by a continuously heating furnace used in heating slabs or the like.
In order to control the temperature of slabs at a delivery end of a heating furnace by an electronic computer, there has been previously employed a method of controlling a low rate of a fuel within the furnace by determining the temperatures of the slab at their different positions occupied thereby between their charge and delivery through a calculation of the heat transfer made on the basis of the temperature of the atmosphere filling the furnace from the slabs' sizes and time intervals for which the slabs are actually put in the furnace, estimating a time interval for which the slabs are left within the furnace until their delivery from delivery schedules for the individual slabs, and calculating back to the necessary temperature of the atmosphere within the furnace required for the slabs to be put at the desired deliver temperature to thereby put the temperature of the atmosphere within the furnace at the desired delivery temperature.
Conventional control methods such as described above have been disadvantageous in that the control has a low accuracy because the calculation of the heat transfer uses a heat transfer coefficient of the slab which is varied with the position and temperature of the slab within the furnace and the particular temperature profile of a burnt fuel and therefore difficult to be treated as a constant. This poor accuracy has also been because the control methods do not consider the influence of the number of slabs existing in each control zone of the furnace and the actual control is effected by using different magnitudes set to the different slabs. This has resulted also in a poor accuracy of the control.
Accordingly, it is an object of the present invention to provide a new and improved control method of controlling the heating effected by a continuously heating furnace with a high accuracy.